With the recent trend to the information society, image displays have become important as information transmitters. To use the displays in various fields, it is necessary for the displays to have low power consumption, a thin profile, lightness in weight, and high resolution.
The displays may be classified into a luminous type and a non-luminous type, where the luminous type displays correspond to, for example, an electro-luminescence (EL) display, a vacuum fluorescent display (VFD), and a plasma display panel (PDP); and the non-luminous type display corresponds to, for example, a liquid crystal display (LCD).
Recently, a flexible display has been introduced, which can be kept folded or rolled without damage. Flexible display technologies are applied to the various displays using a thin film transistor (TFT) LCD device, an organic light-emitting diode (OLED), and an electrophoretic display.
A flexible display is generally referred to as a scroll display. The flexible display is formed with a thin plastic substrate, which can be kept folded or rolled without damage. In this respect, the flexible display is one of next-generation displays. At present, the flexible display is applied to the OLED or the LCD so that the OLED or the LCD can be fabricated by the thin profile, of less than 1 mm.
An OLED can emit the light itself, and can result in good visibility in dark surroundings as well as bright surroundings. Among the currently used displays, the OLED has the most rapid response speed, which is one of most important standards to judge the function of mobile display.
Also, the OLED can be used in mobile devices, for example, mobile phones which can be designed with the ultra-thin profile. To realize the flexible display using the OLED, a flexible substrate of plastic is used.
However, the related art flexible display has the following disadvantages: In order to form the flexible display using the OLED, a flexible substrate of plastic is used. However, the process for fabricating the OLED requires a high-temperature step. The use of the high-temperature step is restricted due to the plastic structure, since the plastic substrate is lower in melting point than the glass substrate, and the patterns for driving the OLED are complex.
To apply a high-temperate processing step to the plastic substrate, a method has been proposed where: a glass substrate is adhered to the plastic substrate, the high-temperature step is applied to the glass substrate, and then the glass substrate is removed from the plastic substrate. In this case, the process is complicated due to the additional steps of adhering the glass substrate to the plastic substrate and removing the glass substrate from the plastic substrate. Also, defective devices and the low yield may occur due to the large number of lamination steps.